Cults in the modern Western world have strong negative connotations, and are often associated with organizations such as the Ku Klux Klan and the Manson Family. Yet, there seems to be an unclear idea of what a cult truly is. For example, Merriam Webster has five different definitions for a cult, with several having sub-definitions as well. The American Psychological Association (APA) also has their own definition, one that follows the lines of colloquial definitions closer than Britannica and Merriam Webster.
The general definition of cult (one that does not take into account cultural connotations) is best seen with the first given definition by Merriam Webster: “a religion regarded as unorthodox or spurious.” However, the APA has a more detailed, more Western idea of cults: “a religious or quasi-religious group characterized by unusual or atypical beliefs, seclusion from the outside world, and an authoritarian structure. Cults tend to be highly cohesive, well organized, secretive, and hostile to nonmembers.”
Cults and religions also walk a fine line between each other. Historically, cults have been subsections of major religions that were particularly dedicated to a particular deity or figure. However, today, religions that are not mainstream are considered cults; there are also plenty of identified cults that are not necessarily religious.
Essentially, there is no good definition of a cult, nor is there one that is collectively used by everyone; you can’t really win when it comes to cults.